Jordin Sparks is mourning the deaths of four close friends and family members, who all passed away this week.

The “No Air” singer posted a tribute to friends Rasual Butler and his wife, Leah, her stepsister Bryanna and her younger cousin on Instagram Thursday.

“Four Angels in a week. My heart is just so heavy & broken. I’m in shock, numb and feel everything all at the same time,” she began her emotional message. “… You were such bright lights in this crazy world. You made everyone better just by knowing them. And your smiles made anyone’s day better. The world is less sparkly without you in it. Rest In Peace and Power. I love you forever.”

Ex-NBA player Butler and his wife were killed in a single-car wreck in California early Wednesday. Her stepsister passed away from complications with sickle-cell anemia. It’s unclear how her cousin died.

“Tomorrow is not promised to any of us. Don’t ever skip a chance to tell someone you appreciate them or how much you love them,” Sparks, who’s pregnant with her first child, continued. “Please, please continue to cover their families and our family with thoughts and prayers. #unicornsdontdie #sicklecellsux.”